Japanese Patent Publication No. 60-59198 discloses a process for producing a sheet with a concavo-convex pattern obtained by thermal expansion of heat-expanding particles. Specifically, Japanese Patent Publication No. 60-59198 discloses anchoring heat-expanding particles in pulp and then aggregating them to form flock, dispersing the flock in a paper-making material containing no heat-expanding particles and making a paper, and then heating the obtained sheet to cause expansion of the heat-expanding particles to form a patterned sheet with a concavo-convex pattern wherein the flock-containing sections have become the expanded bulky sections.